Technical Field
The present invention relates to a resin-molded component which is formed by filling a first molten resin and a second molten resin into a cavity of a mold.
Patent Document 1: Japanese Patent Laid-Open Publication No. 2014-176974
Related Art
For example, as parts of a vehicle lamp, there are various parts such as a lamp housing having a light source disposed therein, a cover for covering the lamp housing, a reflector for reflecting light emitted from the light source, and an extension for achieving the improvement in appearance by shielding internal structures.
These parts of the vehicle lamp often use a resin-molded component which is molded by cooling the molten resin filled in a cavity of a mold having a core mold and a cavity mold (e.g., see Patent Document 1).
Patent Document 1 discloses a technique of filling a first molten resin and a second molten resin into a cavity of a mold and then molding a resin-molded component by a two-color molding. In the two-color molding disclosed in Patent Document 1, first, a first molten resin filled in a first cavity formed by a cavity mold and a first core mold is cooled to mold a primary molded component (first molding part), and then, the first core mold is opened with respect to the cavity mold, and then, a second core mold is clamped to the cavity mold in the state where the primary molded component is set. Subsequently, a second molten resin filled in a second cavity formed by the cavity mold and the second core mold is cooled to mold a second molding part. In this way, a resin-molded component composed of the first molding part and the second molding part is molded.
However, in the case where the resin-molded component is molded by the two-color molding as described above, air present in the second cavity or gas generated from the molten resin, or the like, is pushed to the outside by the second molten resin when the second molten resin is filled in the state where the primary molded component is molded. At this time, depending on the flowing state of the second molten resin or the shape of the primary molded component, or the like, the air or gas is not favorably pushed out, and thus, there is a risk that air bubbles occur between the primary molded component and the second molten resin.
In particular, air bubbles are liable to occur in an end portion in a flowing direction of the second molten resin or in a portion flowing along a convex portion or concave portion of the primary molded component.
The occurrence of such air bubbles becomes a factor of reducing the bonding area between the primary molded component (first molding part) and the second molding part formed by the cooling of the second molten resin. Thus, the bondability between the first molding part and the second molding part is lowered, which makes it difficult to ensure the high strength. Consequently, there is a risk that formability of the resin-molded component is lowered.